Nov. 30A hydrogen fuel cell being tested since February at Dow Chemical Co.'s complex in Freeport has successfully generated electricity using hydrogen that is less than 100 percent pure, which is prompting an expanded test.

Dow and partner General Motors said Monday they are expanding the test to a four-cell pilot plant that could grow in the next 18 months to 2 years to the point that the plant churns out 1 megawatt of power.

Assuming that stage is successful, the companies said Monday, the next stage will be large-scale commercialization, with up to 400 fuel cells installed at Dow plants generating 35 megawatts of electricity, an amount equal to the power used by 25,000 homes. The target date is 2007.

"In the first phase of this project, we collectively learned a lot about generating power from byproduct hydrogen via fuel cell technology, and now we're ready to build on what we've learned," said Gordon Slack, Dow's global business director for energy and climate change. General Motors' interest is in developing fuel cells that could be used for vehicles.

Because it is a byproduct, Dow's hydrogen is less pure than that produced by a laboratory, said Timothy Vail, GM's director of business development for fuel cells.

"The biggest benefit for GM is learning to work with real-world hydrogen that has some impurities in it," he said in a prepared statement.

Although the impurities are low, there was concern that they could damage the cell or the catalysts within it, Slack said.

The four cells already up and running in the pilot plant are expected to tell more about long-term reliability. The companies will also be looking at the possibilities for making use of the waste heat they generate.

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